The decision to develop a Data Analysis and Data management (DADM) Core grew out of the conviction that the Center's science required a coordinated, central source of expertise and resources for the design and implementation of research objects and analysis of data. The Core will provide data analysis and ideas, consider creative solution to challenging problems, and ensure coordination and uniformity among individual projects and investigators. The specific aims of the core are (1) to collaborate with Project Directors to develop and select for each project appropriate research designs, measurement tools, and statistical methodologies for data analysis, (2) develop and implement appropriate standardized instruments for data collection, optimized for batch data entry, (3) Maintain, operate, and provide user support for shared database and computing resources, including a) a common, general-purpose subject tracking system, and b) a daily backup system that provides secure, long-term storage of all project databases, (4) to ensure a uniformed standard of data quality across projects by developing systems to check data rigorously for errors, to report probably errors to project- specific staff, to document all data value changes, and to make corrections to the master database, (5) produce detailed documentation for all master data files and data elements, and (6) review and participate in the writing of abstracts, meeting presentations, and manuscripts.